Patent GB-599739-A (GB)
Title: Improvements relating to electric remote control systems
IPC: B61L7/08
Filed: 1945-05-04
Abstract: 599,739. Railway signalling systems. WESTINGHOUSE BRAKE & SIGNAL CO., Ltd. May 4, 1945, No. 11324. Convention date, June 10, 1944. [Class 105] [Also in Group XXXVIII] In a remote control system e.g. for railway signalling, comprising a central control office connected by a single line circuit to a number of field stations, a station is selectively rendered responsive to the office signals by frequency selective line impulses which cause a counting relay chain at the station to operate sequentially, a further impulse at a different frequency being sent out at an appropriate step in the counting cycle to effect operation of the control relay corresponding to the operative counting relay. As a result the station transmits to the office impulses of another frequency which convey information corresponding to. the control effected by the office and operate lamp signals thereat correspondingly. When a station initiates a signal it first transmits a frequency selective pulse to identify the station followed by pulses at a different frequency to convey the information and operate lamp indicators at the office. Fig. 1 shows the office equipment of a railway traffic control system for transmitting signals in codes of four steps to three or more stations together with the entire control panel for one field station (N.2) and panel portions pertaining to stations Nos. 1, 3.- Fig. 2 shows a typical field station wherein manual block signals LH and RH located at spaced points along a railway track are controlled by polar stick relays LHS, RHS;'the positions of which are indicated at the office by lamps LE; RE. The office panel for each station includes a three-position signal lever such as 2SG operable to a right hand and a left hand position to effect operation of the corresponding signal control relay RHS or LHS to its reverse position, operation of the lever to its normal central position restoring these relays to normal. The passage of a train through a short detector track section T is also reported by the station to the office. Each detector track section T has a normally energised track relay TR and stick repeating relay TS arranged so that each train movement past a clear signal restores it to stop and requires the return of the signal control relay to normal by lever operation at the office. Transmission and reception of office control signals. Assuming that signal RH at station No. 2 is to be cleared, lever 2SG is moved to the right and the. start button 2STB depressed. Normally energised relay 2ST falls off as button 2STB is depressed, and when this button is released, a polar stick relay 2S reverses. Under the assumed conditions, indication relays RGK, LGK, are both energised and the stop indication lamp NE is lighted. Reversal of 2S releases relays RGK, LGK, extinguishes lamp NE and de-energises relay 2SP. As 2SP falls off, a relay 2D picks up and at contacts e of relay 2SP a condenser C12 is connected in the tuning circuit of oscillator OSI so that it will oscillate at a frequency f12 to which only field station No. 2 will respond. Normally energised relay OA is de-energised at contact f of relay 2SP the marking on this contact energising the first relay 01 of slowto-release counting chain relays 01-04. As 01 picks up its contact e closes to connect the oscillator OS1 to the line YZ to begin the first code step. Prior to release of relay OA starting relay 2ST is reenergised and locks over its contact a. At the field station No. 2, Fig. 2, the line re-, lay R1 connected to line through the frequency selective filter F12 picks up and over its contact a energises the first relay 1 of the station counting relay chain 1-4. As relay 1 picks up a slow-to-release relay LB energises, locks up over contact b of relay R1, and provides a stick circuit for R1 at its contacts b. Over contacts d of relay 1 and front contact d of relay TS the primary of a transformer V3 is energised. Relay T3 thereupon operates to connect oscillator OS3 to line YZ to transmit to the office a pulse of frequency f20 to which the office line relay R3, Fig. 1, responds. Over contact a thereof polar stick typerelay TK is energised in its normal direction. Relay OA now releases causing 02 to pick up and de-energising 01. The line impulse at frequency f12 is terminated by opening of contact e of relay 02 whereupon line relay R1 at station No. 2'releases causing counting relay 2 to pick up and relay 1 to release at. the beginning of the second step, the release of 01 at the office marking the end of the second step. As counting relay 01 releases, 02 becomes deenergised, 03 picks up to begin the third step and at its contact e impresses a second impulse of frequency f12 upon the line. At station No. 2, R1 picks up again to energise relay 3 and release relay 2 as the third step begins. At the office, a transformer V1 is energised over contact b of relay 03 and the right hand contact of signal lever 2SG, to transmit over the line during this step a pulse of frequency f10 from oscillator OS2 to which line relay R2 at the selected station responds. Thereupon relay RHS is operated to " reverse " over contacts a, b, a of relays R1, LB, R2 respectively. Over contacts d of relays 3, LHS the transformer V3 is energised to send a further pulse at frequency f20 to the office where relay R3 again responds. Over contact a of relay R3, contacts c, d, d, c, of relays OA, O1, 02, 03, relay LGK is operated and locks temporarily over contacts of released relays OA, 04. When office counter relay 02 releases, 03 is de-energised, and 04 picks up to begin the fourth step. The line impulse at frequency f12 is terminated at contact e of relay 04 to release line relay R1 at station No. 2 whereupon relay 4 picks up and relay 3 releases, LB remaining energised as it is slow-to-release. The control and indication channels remain open on this step. When relay 03 at the office falls off to terminate the code, relay OA picks up and relay 2S is energised to normal whereupon the normal stick circuit for relay LGK is made at contact b thereof. Relay 2SP picks up and at its contact g release relay 2D to disconnect lever 2SG and the associated indication relays pertaining to station No. 2 from the counting relays 01-04. At its contact a relay 2D lights the lamp LE. Relay 04 now releases toÀ switch at its contacts a the circuit for holding relay OA to the branch including the f contacts of the relays 1SP, 2SP corresponding to the stations Nos. 1, 2, and if these relays are all picked up relay OA remains energised and the office apparatus remains in its normal position. At the station No. 2 relays LB and 4 release to restore the station to normal. Should one of the relays 1SP, 2SP be in released position, however, relay OA becomes de-energised as 04 releases to recommence the sequential energisation of the counting relays O1-O4 to deliver a second code to the station corresponding to the released relay SP. It will be seen that when the push button 1STB, 2STB for any -particular station is depressed the oscillator OS1 is tuned over a contact e of the associated relay SP to transmit a frequency selective impulse so that the line relay R1 at the selected station only responds and the counting relays 1-4 thereat are operated in sequence in step with the counting relays 01-04 at the office which being slow to release effect the timing. Dependent on the position of the signal lever 2SG of the selected station office panel the control impulse at frequency f10 is sent over the line during the first, second or third step of the control code. Relays 1, 2, 3 at the selected station being operated respectively during these steps, the control signal is passed over contact a or b of relay R2 and the operative c contact of the counting relay 1, 2 or 3 to operate respectively (1) both re-. lays LHS, RHS to normal (II) relay LHS to " reverse " or (III) relay RHS to " reverse " according to the position of the signal lever SG on the office panel. Transmission and reception of indication (station) signals. Should a train moving towards the right, Fig. 2, pass the signal RH at clear normally energised relay TR is released and in turn releases relays TS, ST, thereby energising relay STP which causes relay T3 to connect oscillator OS3 to deliver an. impulse to line of frequency f22. This frequency which is determined by the tuning condenser C22 switched in circuit by relay STP, identifies the station at the office where the signal is accepted by the corresponding filter f22, Fig. 1, and actuates relay 2S to reverse. Relay 2S releases 2SP to initiate the transmission of a code similar to that above described except that the starting relay 2ST has not been released and the indication impulse of frequency f20 by which office line relay R3 is operated is delivered on the second code step instead of the first as relay TS at station No. 2 is released. This impulse is passed by R3 to the lower winding of and reversed relay TK and lights lamp TKE located in the portion of a miniature track diagram corresponding to the detector track portion T, Fig. 2, to indicate the presence of the'train. The signal indication lamps are extinguished for the duration of the code as before. Assuming that the operator now restores lever 2SG to normal and operates button 2STB, a control code is initiated. as above described in which an impulse of frequency f10 is supplied during the first step to restore relay RHS to normal. The indication relays LGK, RGK pick up during the third and fourth steps, lighting lamp NE. When the train vacates the detector section T, relay TR picks up, whereupon TS picks up and initiates a code-which includes an indication impulse on the first step to restore relay TK. Fig. 1, to normal to extinguish lamp TKE. Signal LH is controlled in a similar manner to RH. Preventing interference between stati